Exploring the possibilities of double proton transfer in hydrazides: A theoretical approach. (9th August 2019)

• Record Type: Journal Article
• Authors: Mohan, Makesh; Satyanarayan, M.N.; Trivedi, Darshak R.
• Is Part Of: Journal of physical organic chemistry. Volume 32:Number 11(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-09
• Subjects: DFT -- ESIPT -- PES -- photoluminescence -- TDDFT; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.4003
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: Hydrazides are known to exhibit keto‐enol tautomerism upon photoexcitation. Theoretical aspects uncovering excited state intramolecular proton transfer (ESIPT) of N‐acylsubstituted hydrazides with bithiophene core have been investigated. Geometrical aspects of the system are expected to undergo double proton translocation at its excited state. However, potential energy surface study for all the molecules reveals an impossible concurrent double proton translocation and to a greater extent dubious step‐wise double proton translocation in the system. Potential energy scans reveal molecules possessing a lower forward barrier at its excited state in comparison with their ground state suggestive of possible excited state single proton transfer. Geometrical attributes and spectral analysis suggest the strengthening of intramolecular hydrogen bond (N―H▪▪▪O) at its excited state, favoring single proton translocation. Theoretical estimation of electronic energy transition for all the conformers yields good correlation with the experimental figures with an energy overestimation <0.17 eV. Abstract : Hydrazides undergo keto‐enol tautomerism and theoretical aspects uncovering the excited state intramolecular proton transfer (ESIPT) phenomena is explored in the present work. Geometrical aspects of the system is expected to support simultaneous double proton transfer upon photoexcitation. Potential energy surface study on the system reveals an impossible simultaneous double proton transfer and a doubtful stepwise double proton transfer. Potential energy scans on molecules reveal system to support single proton transfer at its excited state.